The field of protein kinase C catapulted to the forefront of signal transduction with the discovery two decades ago that this enzyme transduces the myriad of extracellular signals that promote phospholipid hydrolysis. Since then, intense efforts have been devoted to understanding the structure, function, and regulation of this key enzyme. Yet, it is only in the past few years that major discoveries have started unveiling the complex regulation and function of the enzyme. In particular, the past year has been marked by the unanticipated discovery that protein kinase C is, itself, regulated by the phosphoinositide-dependent protein kinases, providing a new mechanism of regulation by lipid that is independent of the known regulation by diacylglycerol. This past year was also marked by the demonstration that disruption of a scaffold protein disrupts an entire signalling cascade, thus underscoring the importance of anchoring proteins. The development of techniques to study the activation of protein kinase C in real time has also poised the field to understand cellular signalling by this enzyme. The goals of this meeting are to address the recent advances in protein kinase C's structure, regulation, and cellular function. This meeting will have an added impact by synergizing with the Lipid Second Messenger Meeting organized by George Carman. Three key aspects of the proposed meetings are: 1. It is unique in that a) it will integrate cell biological, biochemical, structural, and biophysical advances in understanding protein kinase C and b) will synergize with the joint Lipid Second Messenger Meeting, providing new insight into the role of 2 independent lipid signalling pathways, the established phospholipase C one and the newly discovered phosphoinositide-3 kinase one, in regulating protein kinase C. This meeting is most similar to the 1994 Keystone Meeting on protein kinase C that was held jointly with one on lipid second messengers. 2. It is multidisciplinary in that it interfaces structural, mechanistic, and cell biological aspects of protein kinase C signalling. The leading researchers in these fields will be invited to participate. 3. It will set the agenda for future directions in the blossoming field of understanding the in vivo regulation and function of protein kinase C, which will be invaluable to graduate students and postdoctoral fellows in embarking upon their own careers.